Zirconium Catalyzed Ethylene Oligomerization

A review of the scientific and patent literature on oligomerization of ethylene to linear olefins in the presence of homogenous or heterogeneous zirconium complexes and various aluminum organic compounds has been fulfilled for last twenty-five years. Over these years, a wide range of studies had been conducted for selective oligomerization of ethylene into a narrow fraction of linear α-olefins such as C₄-C₈ and C₆-C₁₀ fractions. During the discussion of these catalytic systems, exceptional attention is also paid to feature works such as the activity of the catalysts and the acquisition of clear liquid product without any trace of polymer, all of which play important roles in the selection of the best technology.     

KHPO4/ultrasonic irradiation catalyzed multicomponent synthesis of aminocyanopyrano[3,2-b]indole

Potassium dihydrogen phosphate (KH₂PO₄) with the aid of ultrasonic irradiation was found to be an efficient catalytic system for the efficient and rapid synthesis of novel 2-amino-4,5-dihydro-4-arylpyrano[3,2-b]indole-3-carbonitriles.     

Synthesis, characterization and application of β-cyclodextrin-silica nanocomposite as potential microvessel in nucleophilic substitution reaction of phenacyl halides

In the present study, β-cyclodextrin-silica hybrid is synthesized as a novel, efficient and eco-friendly microvessel and solid–liquid phase-transfer catalyst. This molecular host system was applied for nucleophilic substitution reaction of phenacyl halides in water. No evidence was observed for the formation of by-product for example isothiocyanate or alcohol. Also the products were obtained in pure form without further purification. The structure and morphology of the obtained system were investigated by infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis and differential thermal analysis techniques. The surface porosity of the synthesized catalyst was evaluated from the nitrogen adsorption isotherm. All the results provided evidence for incorporation of β-cyclodextrin inside silica pores.     

Synthesis of Biginelli Compounds Using Cobalt Hydrogen Sulfate

Efficient synthesis of various 2‐oxo(thioxo)‐1,2,3,4‐tetrahydropyrimidines containing acetyl, carboethoxy, carbomethoxy and carboxamide groups on 5‐position of the N1‐substituted and N1‐unsubstituted heterocyclic ring was achieved using cobalt hydrogen sulfate Co(HSO₄)₂ under thermal conditions. Good to high yield, shorter reaction times, easy work up and simple preparation of Co(HSO₄)₂ are the advantages using this synthetic method.     

Approximation of fuzzy integrals using fuzzy bernstein polynomials

In this paper, we approximate the integration of continuous fuzzy real number valued function of one and two variables. To do this, we use Bernstein-type fuzzy polynomials. Moreover, we obtain the error estimates for these approximations in terms of the modulus of continuity.